A review of the origins of longitudinal research in trial courts traces it to theories of law and social change having their roots in 19th-century European social theory. This tradition was reflected in American legal history. The contributions of various researchers are cited, notably Friedman and Percival's work, which defined the field of longitudinal trial court research in its early stages and encourages both the field's methodological emphasis on docket data and its theoretical orientation toward the effects of economic development on litigation. This review notes criticisms of the slow fruition of longitudinal studies of trial courts as attributable to methodological obstacles. A more fundamental problem identified is the contemporary emergence of conflicting, yet incompletely articulated, paradigms for empirical research on law. This has made researchers cautious about formulating tentative generalizations of the kind longitudinal research requires for data collection and analysis. This introduction concludes with an overall assessment of longitudinal research on trial courts and a summary of the subsequent articles.